It is easy to forget, as one views the skyline of modern Tucson, that our community has its origins in a small Spanish fortress. In 1775, Captain Hugo O'Conor selected a piece of land on the east side of the Santa Cruz River for a presidio. Over the next eight years adobe walls were built to enclose the area to protect people inside the fort from Apache attacks.

Today the walls are lost, buried in the heart of Tucson below streets, lawns, sidewalks, and buildings. In order to find them, we must examine historic documents and old photographs, excavate trenches, and study artifacts.

Over the last 10 years, the Center for Desert Archaeology has initiated several research projects to look for remains of Tucson's Presidio. In 1991 we worked with Karl Glass of the University of Arizona on a ground-penetrating radar study that suggested that portions of the Presidio wall were intact beneath the ground surface in several areas. The following year, Center volunteers helped excavate trenches in the Pima County Courthouse courtyard, ultimately exposing a north-south adobe wall which rests on a stone foundation. This is thought to be the east Presidio wall, perhaps a portion dating to the remodeling of the wall in the 1820s.

The City of Tucson recently acquired the northeast corner area of the Presidio, which lies beneath a parking lot. The City and Pima County have ordinances protecting cultural resources; however, development activities, such as utility installation, can still impact Presidio period archaeological remains. A better understanding of what lies buried beneath the ground will aid in the development of a master plan for the Presidio area, helping guide future activities.

In March and April 1998, the Center returned to search for portions of the south, west, and north walls of the Presidio. Trenches were excavated in five areas by volunteers who carefully screened dirt and bagged artifacts. Undisturbed archaeological deposits were found in most areas. Especially exciting was the discovery of a complex of features in the lawn area on the west side of the City Hall.